Distribuição espacial da pressão na lateral de um pivô central com base em um modelo digital de elevação (MDE)

The spatial distribution of pressure head values along a 432,6m long center pivot lateral line was determined using measured values, taken at the inlet and end sections of the lateral line, and combined with topographic elevation data from a SRTM (Shuttle Radar Topography Mission) image. Data furnished by SRTM describes topographic elevation values along the wheel tracks of each one of the eight towers used for the sustentation of the center pivot lateral line. For validation purposes of the process used for the determination of the pressure head distribution along the lateral line length, on 18 angular positions equally spaced along a complete turn of the lateral line, values of pressure head were also measured on 6 distinct points of the lateral line. Differences, on a 5% signiï¬cance level for the student t means test, were observed when measured values were compared to pressure head values estimated based on SRTM's altitude data. After the creation of thematic maps, there was a coincidence in the positioning of the regions of occurrence of the highest of pressure head, also, the lower pressure head values. The study demonstrates that the use of elevation data from SRTM images is acceptable only for the elaboration of thematic maps destined to delimit within the irrigated area the occurrence of regions where different pressure head values prevailed.A distribuição espacial da carga de pressão ao longo dos 432,6m de comprimento de uma linha lateral de um pivô central foi determinada a partir de valores medidos, na entrada e na extremidade da linha lateral, e combinados com dados de altitude proveniente de uma imagem SRTM do rastro das oito torres de sustentação da linha lateral. Para fins de validação da estimativa da distribuição espacial da carga de pressão na linha lateral móvel, em 18 diferentes posições angulares, foram medidos valores de carga de pressão em seis pontos distintos do seu comprimento. Diferenças significativas, ao nível de 5% do teste de médias “t de student”, foram observadas quando valores de carga de pressão estimados com dados de altitude do SRTM foram comparados com os valores medidos em campo. Após a confecção de mapas temáticos verificou-se coincidência no posicionamento das regiões de ocorrência dos valores mais elevados, como também dos menores valores de carga de pressão. O estudo demonstrou que o uso de dados de elevação a partir de imagens SRTM é aceitável apenas para a elaboração de mapas temáticos destinados a delimitar dentro da área irrigada a ocorrência de regiões onde prevaleceram valores de pressão distintos

Use of remotely piloted aircraft in precision agriculture: a review

The objective of this review was to examine the current use of remotely piloted aircraft (RPA) in obtaining data to assist in the application of precision farming techniques and to exemplify successful situations of technology use. The RPA has applications for monitoring, mapping, vegetation index (VI) extraction, volume, plant height, among others, and has been studied in several agricultural crops, being support for decision making on agrochemical application, planting failure, accompaniment of growth favoring the increase of crop productivity. One of the potentialities evaluated through RPA is the use of VI, which may be extracted from digital images obtained by cameras that contain only the visible band. It may be an alternative for farmers who do not have access to RPA coupled with high-tech embedded sensors. Therefore, it is a tool that may contribute to the decision making, allowing the acquisition of high spatial and temporal resolution imagesEl objetivo de esta revisión fue examinar el uso actual de aeronaves pilotadas remotamente (RPA) en la obtención de datos para aplicaciones de la agricultura de precisión, ejemplificando situaciones exitosas de uso de la tecnología. La RPA tiene aplicaciones para monitoreo, mapeo, extracción de índice de vegetación (VI), volumen, altura de plantas, y ha sido estudiado en diversas culturas agrícolas, siendo soporte para toma de decisión sobre aplicación de agroquímicos, falla de plantación, acompañamiento del crecimiento y aumento de la productividad. Un potencial evaluadas por la RPA es el uso del VI, que puede ser extraído de imágenes digitales obtenidas por cámaras que contienen la banda visible. Siendo una alternativa para los agricultores que no tienen acceso a RPA acoplado a sensores de alta tecnología. Por lo tanto, es una herramienta que puede contribuir a la toma de decisiones, permitiendo la adquisición de imágenes de alta resolución espacial y tempora

Estimate and Temporal Monitoring of Height and Diameter of the Canopy of Recently Transplanted Coffee by a Remotely Piloted Aircraft System

Digital agriculture is fundamental to potential improvements in the field by optimizing processes and providing intelligent decision making. This study aims to calculate the height and canopy diameter of recently transplanted coffee plants over three periods of crop development using aerial images, verify statistical differences between field measurements and aerial images, estimate linear equations between field data and aerial images, and monitor the temporal profile of the growth and development of the cultivar understudy in the field based on information extracted from aerial images through a Remotely Piloted Aircraft System (RPAS). The study area comprises a recently transplanted five-month-old Coffea arabica L. cultivar IAC J10 with information of height and crown diameter collected in the field and aerial images obtained by RPAS. As a result, it was possible to calculate the height and diameter of the canopy of coffee plants by aerial images obtained by RPAS. The linear estimation equation for height and crown diameter was determined with satisfactory results by coefficients R and R2 and performance metrics MAE, RMSE, and regression residuals, and it was possible to monitor the temporal profile of the height of the coffee cultivar in the field based on aerial images

Estimate and Temporal Monitoring of Height and Diameter of the Canopy of Recently Transplanted Coffee by a Remotely Piloted Aircraft System

Digital agriculture is fundamental to potential improvements in the field by optimizing processes and providing intelligent decision making. This study aims to calculate the height and canopy diameter of recently transplanted coffee plants over three periods of crop development using aerial images, verify statistical differences between field measurements and aerial images, estimate linear equations between field data and aerial images, and monitor the temporal profile of the growth and development of the cultivar understudy in the field based on information extracted from aerial images through a Remotely Piloted Aircraft System (RPAS). The study area comprises a recently transplanted five-month-old Coffea arabica L. cultivar IAC J10 with information of height and crown diameter collected in the field and aerial images obtained by RPAS. As a result, it was possible to calculate the height and diameter of the canopy of coffee plants by aerial images obtained by RPAS. The linear estimation equation for height and crown diameter was determined with satisfactory results by coefficients R and R2 and performance metrics MAE, RMSE, and regression residuals, and it was possible to monitor the temporal profile of the height of the coffee cultivar in the field based on aerial images

Spatial variability of soil pH sampled by two methodologies used in precision agriculture in farms under crop rotation

This study aimed to characterize the spatial variability of pH in soils of two farms in the state of Paraná, Brazil, based on two different sampling methods used in precision agriculture, by means of geostatistical analyzes. The first method of sampling the pH grid consisted in the collection of soil samples by the traditional method (1 point / ha). The second method of pH determination was by on-the-go soil sensor (200 points / ha). The spherical model was better suited to most semivariograms, regardless of the sampling method. After adjusting the semivariograms for soil pH determination methods, thematic maps were made using normal kriging. The best spatial distribution of pH was obtained where the attribute was sampled by the on-the-go sensor. The number of pH samples collected and the sampling method influenced the visual representation of pH variabilityEl objetivo de este estudio fue caracterizar la variabilidad espacial del pH para suelos de dos fincas en el estado de Paraná, Brasil, con base en dos métodos diferentes de muestreo utilizados en agricultura de precisión, mediante análisis geoestaddísticos. El primero método de muestreo del pH consistió en la colecta de muestras de suelo por ele método tradicional (1punto/ha). El segundo método de determinación del pH fue el sensor de suelo dinâmico (200 puntos / ha). El modelo esférico fue más adecuado para la mayoría de los semivariogramas, independientemente del método de muestreo. La mejor distribución espacial fue obtenida por la cualidad del muestreado del sensor de suelo dinâmico. El número de muestras del pH colectadas y el método de muestreo influyeron en la representación visual de la variabilidad del p